DIY projects that were made with older versions of the LabQuest SDK (NGIO_lib) will not be able to communicate with a LabQuest or LabQuest Mini over USB if a newer USB device driver has been installed by another application. The newer USB device drivers were first distributed in May, 2016 by the following products:

You will then need to replace all occurrences of the SDK that are associated with your project with the files from the new version. The communication library is named NGIO_lib.dll, and is the probably the only file you really need to replace.